Integrated epitaxy and preclean system

ABSTRACT

Implementations of the present disclosure generally relates to a transfer chamber coupled to at least one vapor phase epitaxy chamber a plasma oxide removal chamber coupled to the transfer chamber, the plasma oxide removal chamber comprising a lid assembly with a mixing chamber and a gas distributor; a first gas inlet formed through a portion of the lid assembly and in fluid communication with the mixing chamber; a second gas inlet formed through a portion of the lid assembly and in fluid communication with the mixing chamber; a third gas inlet formed through a portion of the lid assembly and in fluid communication with the mixing chamber; and a substrate support with a substrate supporting surface; a lift member disposed in a recess of the substrate supporting surface and coupled through the substrate support to a lift actuator; and a load lock chamber coupled to the transfer chamber.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. Ser. No.16/100,399, filed Aug. 10, 2018, which claims benefit of U.S.Provisional Patent Application Ser. No. 62/552,107, filed Aug. 30, 2017,both of which are hereby incorporated by reference herein.

FIELD

Implementations of the present disclosure generally relate to anapparatus and a method for cleaning a surface of a substrate.

BACKGROUND

Integrated circuits are formed in and on silicon and other semiconductorsubstrates. In the case of single crystal silicon, substrates are madeby growing an ingot from a bath of molten silicon, and then sawing thesolidified ingot into multiple substrates. An epitaxial silicon layermay then be formed on the monocrystalline silicon substrate to form adefect free silicon layer that may be doped or undoped. Semiconductordevices, such as transistors, may be manufactured from the epitaxialsilicon layer. The electrical properties of the formed epitaxial siliconlayer are generally better than the properties of the monocrystallinesilicon substrate.

Surfaces of the monocrystalline silicon and the epitaxial silicon layerare susceptible to contamination when exposed to typical substratefabrication facility ambient conditions. For example, a native oxidelayer may form on the monocrystalline silicon surface prior todeposition of the epitaxial layer due to handling of the substratesand/or exposure to ambient environment in the substrate processingfacility. Additionally, foreign contaminants such as carbon and oxygenspecies present in the ambient environment may deposit on themonocrystalline surface. The presence of a native oxide layer orcontaminants on the monocrystalline silicon surface negatively affectsthe quality of an epitaxial layer subsequently formed on themonocrystalline surface. It is therefore desirable to pre-clean thesubstrates in order to remove the surface oxidation and othercontaminants before epitaxial layers are grown on the substrates.However, pre-clean processes are often carried out in one or morestand-alone vacuum process chambers, which may increase substratehandling time and chances of exposing substrates to ambient environment.

Therefore, there is a need in the art to provide an improved substrateprocessing system for cleaning a substrate surface prior to performingan epitaxial deposition process that minimizes substrate handling timeand exposure to ambient environment.

SUMMARY

This disclosure describes a processing system, comprising a transferchamber coupled to at least one film formation chamber; a plasma oxideremoval chamber coupled to the transfer chamber, the plasma oxideremoval chamber comprising a remote plasma source and a substratesupport comprising a cooling channel and a heater; and a load lockchamber coupled to the transfer chamber.

Also described herein is a method of processing a substrate, comprisingremoving oxide from a substrate by a process that includes exposing thesubstrate to a processing gas comprising NH₃, HF, and radicals; andforming a film on the substrate by a vapor phase epitaxy process.

Also described herein is a processing apparatus, comprising a firsttransfer chamber coupled to at least one vapor phase epitaxy chamber; aplasma oxide removal chamber coupled to the transfer chamber, the plasmaoxide removal chamber comprising a lid assembly with a mixing chamberand a gas distributor; a first gas inlet formed through a portion of thelid assembly and in fluid communication with the mixing chamber; asecond gas inlet formed through a portion of the lid assembly and influid communication with the mixing chamber; a third gas inlet formedthrough a portion of the lid assembly and in fluid communication withthe mixing chamber; and a substrate support with a substrate supportingsurface; a cooling channel and one or more resistive heaters embedded inthe substrate support; and a lift member disposed in a recess of thesubstrate supporting surface and coupled through the substrate supportto a lift actuator; and a load lock chamber coupled to the transferchamber.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present disclosure, briefly summarized above anddiscussed in greater detail below, can be understood by reference to theillustrative implementations of the disclosure depicted in the appendeddrawings. It is to be noted, however, that the appended drawingsillustrate only typical implementations of this disclosure and aretherefore not to be considered limiting of its scope, for the disclosuremay admit to other equally effective implementations.

FIG. 1 illustrates a processing sequence in accordance with oneimplementation of the present disclosure.

FIG. 2A is a cross-sectional view of a cleaning chamber used to performa cleaning process of FIG. 1 in accordance with one implementation ofthe present disclosure.

FIG. 2B is an enlarged view of a portion of the processing chamber ofFIG. 2A.

FIG. 2C is an enlarged cross-sectional view of a substrate supportaccording to one embodiment.

FIG. 3 illustrates single substrate chemical vapor deposition (CVD)reactor for performing an epitaxial deposition process.

FIG. 4 illustrates a schematic sectional view of a backside heatingprocess chamber for performing an epitaxial deposition process.

FIG. 5 is a schematic cross-sectional view of a CVD chamber forperforming an epitaxial deposition process.

FIG. 6 illustrates an exemplary vacuum processing system for performingcleaning and deposition processes as described herein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. The figures are not drawn to scale and may be simplifiedfor clarity. It is contemplated that elements and features of oneimplementation may be beneficially incorporated in other implementationswithout further recitation.

DETAILED DESCRIPTION

FIG. 1 illustrates a processing sequence 100 in accordance with oneimplementation of the present disclosure. In box 102, oxides are removedfrom a surface of a semiconductor substrate using a cleaning process.The substrate may include a silicon containing material and the surfacemay include a material, such as silicon (Si), germanium (Ge) or silicongermanium alloys (SiGe). In some implementations, the Si, Ge, or SiGesurface may have an oxide layer, such as a native oxide layer, andcontaminants disposed thereon. Due to the sensitivity of epitaxialdeposition processes to oxides and contaminants, such as carboncontaining contaminants, surface contamination resulting from exposureto most typical cleanroom environments for a few hours can becomesignificant enough for the accumulated oxides and contaminants to affectthe quality of a subsequently formed epitaxial layer.

The substrate surface may be cleaned by performing an oxides removalprocess and a contaminant removal process. In one implementation, theoxides are removed from the surface of the substrate using a cleaningprocess (box 102), and the contaminants, such as carbon containingcontaminants, are removed from the surface of the substrate using areducing process, for example. The cleaning process may include a plasmaprocess. The plasma process may use a plasma formed form a gas includinghydrogen (H₂), helium (He), argon (Ar), ammonia (NH₃), a fluorinecontaining gas such as NF₃, HF, or any combination of these gases. Theplasma may be inductively or capacitively coupled, or the plasma may beformed by a microwave source in a processing chamber. The processingchamber may be a remote plasma chamber that is spatially separated froma processing region in which the substrate is disposed. The term“spatially separated” described herein may refer to a plasma formationregion that is separated from a substrate processing region by one ormore chamber components such as a blocker plate 228 and a gasdistributor 230 shown in FIG. 2A, or even a conduit between a remoteplasma chamber and a substrate processing chamber.

In one implementation, the plasma is formed using a capacitively coupledplasma source. Radicals from the plasma may pass through a gasdistribution plate disposed above the substrate, which is positioned ona support at a temperature of about 5 degrees Celsius to about 100degrees Celsius, such as a temperature of about 5 degrees Celsius toabout 75 degrees Celsius, for example about 10 degrees Celsius. Theprocessing pressure may be at subatmospheric pressure, for example apressure between about 500 mTorr and about 20 Torr, such as betweenabout 2 Torr and about 10 Torr. Radicals reach the substrate and thenreact with the surface oxides. Exemplary processing chambers that can beadapted to perform the plasma etching process include the SiCoNi™ orSelectra™ chambers, which are available from Applied Materials, Inc., ofSanta Clara, Calif. Chambers from other manufacturers may also be used.

In one exemplary implementation, the plasma cleaning process is a remoteplasma assisted dry cleaning process which involves the concurrentexposure of a substrate to HF and NH₃, optionally including plasmaby-products of one or more of the gases. Inert gases such as argon andhelium may also be used. Any one, or combination of the three gases,inert/HF/NH₃ may be exposed to energy, as described above, to form aplasma thereof. The plasma is mixed with the other gases for charging tothe process chamber, or the plasma and other gases may be provided tothe process chamber along different pathways, mixing upon arrival to theprocess chamber. In one example, the plasma cleaning process may besimilar to or may include a SiCoNi™ process that is available fromApplied Materials, Inc., of Santa Clara, Calif.

The remote plasma process can be largely conformal and selective foroxide layers, and thus does not readily etch silicon, germanium, ornitride layers regardless of whether the layers are amorphous,crystalline or polycrystalline. Selectivity of the HF/NH₃ plasmacleaning process for oxide versus silicon or germanium is at least about3:1, and usually 5:1 or better, sometimes 10:1. The HF/NH₃ plasmacleaning process is also highly selective of oxide versus nitride. Theselectivity of the HF/NH₃ plasma cleaning process versus nitride is atleast about 3:1, usually 5:1 or better, sometimes 10:1.

In some embodiments, either during the remote plasma process or afterperforming the remote plasma process, an amount of thermal energy can beapplied to the processed substrate to help remove any generatedby-products. In some embodiments, the thermal energy is provided via aradiant, convective and/or conductive heat transfer process that causesthe unwanted by-products found on the substrate surface to sublimate.

In optional box 103, a second cleaning process may be performed byremoving carbon contaminants from the surface of the substrate. In box106, an epitaxial layer is formed on the surface of the substrate. Ifcleaned prior, as described above, the surface of the substrate isuniformly oxide and contaminant free which improves the quality oflayers subsequently formed on the surface of the substrate. An exemplaryepitaxial process may be a selective epitaxial process performed at atemperature that is less than about 800 degrees Celsius, for exampleabout 450 to 650 degrees Celsius. The epitaxial layer may be formedusing a high temperature chemical vapor deposition (CVD) process. Theepitaxial layer may be a crystalline silicon, germanium, or silicongermanium, or any suitable semiconductor material such as a Group III-Vcompound or a Group II-VI compound. In one exemplary thermal CVDprocess, processing gases such as chlorosilanes SiH_(x)Cl_(4-x) (mono,di, tri, tetra), silanes Si_(x)H_(2X+2) (silane, disilane, trisilane,etc.), germanes Ge_(x)H_(2x+2) (germane, digermane, etc.), hydrogenchloride HCl, chlorine gas Cl₂, or combinations thereof are used to formthe epitaxial layer. The processing temperature is under 800 degreesCelsius, such as about 300 degrees Celsius to about 600 degrees Celsius,for example about 450 degrees Celsius, and the processing pressure isbetween 5 Torr and 600 Torr. An exemplary processing chamber that can beused to perform the epitaxial deposition process is the Centura™ Epichamber, which is available from Applied Materials, Inc., of SantaClara, Calif. Chambers from other manufacturers may also be used.

Boxes 102, 103 and 106 may be performed in one processing system, suchas the processing system illustrated in FIG. 9, and further describedbelow. An optional thermal treatment may also be performed between orafter the processes 102 and 103, before performing the layer formationprocess of 106, to remove any residual by-products or contaminants, andto anneal the surface to remove any surface defects. Such an anneal maybe performed under a hydrogen atmosphere, optionally including an inertgas such as argon and helium, and may be performed at temperatures of400 to 800 degrees Celsius and pressures from 1 Torr to 300 Torr.

FIG. 2A is a cross sectional view of a processing chamber 200 that isadapted to perform at least some of the processes found in box 102, andthus is configured to remove contaminants, such as oxides, from asurface of a substrate. FIG. 2B is an enlarged view of a portion of theprocessing chamber 200 of FIG. 2A.

The processing chamber 200 may be particularly useful for performing athermal or plasma-based cleaning process and/or a plasma assisted dryetch process. The processing chamber 200 includes a chamber body 212, alid assembly 214, and a support assembly 216. The lid assembly 214 isdisposed at an upper end of the chamber body 212, and the supportassembly 216 is at least partially disposed within the chamber body 212.A vacuum system can be used to remove gases from processing chamber 200.The vacuum system includes a vacuum pump 218 coupled to a vacuum port221 disposed in the chamber body 212. The processing chamber 200 alsoincludes a controller 202 for controlling processes within theprocessing chamber 200.

The lid assembly 214 includes a plurality of stacked componentsconfigured to provide precursor gases and/or a plasma to a processingregion 222 within the chamber 200. A first plate 220 is coupled to asecond plate 240. A third plate 244 is coupled to the second plate 240.The lid assembly 214 may be connected to a power source 224 forsupplying a plasma to a cone-shaped chamber 242 formed in the lidassembly 214. The lid assembly 214 can also be connected to a remoteplasma source that creates the plasma upstream of the lid stack. Theremote plasma cavity (e.g., items 222, 220, 240 in FIGS. 2A-2B) iscoupled to a gas source 252 (or the gas source 252 is coupled directlyto the lid assembly 214 in the absence of the remote plasma source 224).The gas source 252 may include a gas source that is configured toprovide helium, argon, or other inert gas. In some configurations, thegas provided by the gas source 252 can be energized into a plasma thatis provided to the lid assembly 214 by use of the remote plasma source224. In alternate embodiments, the gas source 252 may provide processgases that can be activated by the remote plasma source 224 prior tobeing introduced to a surface of the substrate that is disposed withinthe processing chamber 200. Referring to FIG. 2B, the cone-shapedchamber 242 has an opening 246 that allows a formed plasma to flow fromthe remote plasma source 224 to a volume 248 formed in a fourth plate250 of the lid assembly 214.

In some configurations of the lid assembly 214, a plasma is generatedwithin the cone-shaped chamber 242 by the application of energydelivered from a plasma source. In one example, the energy can beprovided by biasing the lid assembly 214 to capacitively couple RF, VHFand/or UHF energy to the gases positioned in the cone-shaped chamber242. In this configuration of the lid assembly 214, the remote plasmasource 224 may not be used, or not be installed within the lid assembly214.

A central conduit 270, which is formed in fourth plate 250, is adaptedto provide the plasma generated species provided from the volume 248through a fifth plate 254 to a mixing chamber 266 formed in a sixthplate 268 of the lid assembly 214. The central conduit 270 communicateswith the mixing chamber 266 through an opening 264 in the fifth plate254. The opening 264 may have a diameter less than, greater than or thesame as a diameter of the central conduit 270. In the embodiment of FIG.2B, the opening 264 has diameter the same as the central conduit 270.

The fourth plate 250 also includes a plurality of inlets 256 and 258that are configured to provide gases to the mixing chamber 266. Theinlet 256 is coupled to a first gas source 260 and the inlet 258 iscoupled to a second gas source 262. The first gas source 260 and thesecond gas source 262 may include processing gases as well as inertgases, for example noble gases such as argon and/or helium, utilized asa carrier gas. The first gas source 260 may include ammonia (NH₃) aswell as argon. The second gas source 262 may contain fluorine containinggases, hydrogen containing gases, or a combination thereof. In oneexample, the second gas source 262 may contain hydrogen fluoride (HF) aswell as argon.

As illustrated in FIG. 2B, in some configurations, the inlet 256 iscoupled to the mixing chamber 266 through a cylindrical channel 259(shown in phantom) and a plurality of holes 265 formed in the plate 254.The inlet 258 is coupled to the mixing chamber 266 through a cylindricalchannel 257 (shown in phantom) and a plurality of holes 267 formed inthe fifth plate 254. The holes 265, 267 formed in the plate 254 aregenerally sized so that they enable a uniform flow of gases, which areprovided from their respective gas source 260, 262, into the mixingchamber 266. In one configuration, the holes 267 have a diameter that isless than a width of the opening defined by the opposing sidewalls ofthe cylindrical channel 257 formed fourth plate 250. The holes 267 aretypically distributed around the circumference of the center-line of thecylindrical channel 257 to provide uniform fluid flow into the mixingchamber 266. In one configuration, the holes 265 have a diameter that isless than a width of the opening defined by the opposing sidewalls ofthe cylindrical channel 259 formed fourth plate 250. The holes 265 aretypically distributed around the circumference of the center-line of thecylindrical channel 259 to provide uniform fluid flow into the mixingchamber 266.

The inlets 256 and 258 provide respective fluid flow paths laterallythrough the fourth plate 250, turning toward and penetrating through thefifth plate 254 to the mixing chamber 266. The lid assembly 214 alsoincludes a seventh plate or first gas distributor 272, which may be agas distribution plate, such as a showerhead, where the various gasesmixed in the lid assembly 214 are flowed through perforations 274 formedtherein. The perforations 274 are in fluid communication with the mixingchamber 266 to provide flow pathways from the mixing chamber 266 throughthe first gas distributor 272. Referring back to FIG. 2A, a blockerplate 228 and a gas distribution plate, such as a second gas distributor230, which may be a gas distribution plate, such as a showerhead, isdisposed below the lid assembly 214.

Alternatively, a different cleaning process may be utilized to clean thesubstrate surface. For example, a remote plasma containing He and NH₃may be introduced into the processing chamber 200 through the lidassembly 214, while NH₃ may be directly injected into the processingchamber 200 via a separate gas inlet 225 that is disposed at a side ofthe chamber body 212 and coupled to a gas source (not shown).

The support assembly 216 may include a substrate support 232 to supporta substrate 210 thereon during processing. The substrate support 232 maybe coupled to an actuator 234 by a shaft 236 which extends through acentrally-located opening formed in a bottom of the chamber body 212.The actuator 234 may be flexibly sealed to the chamber body 212 bybellows (not shown) that prevent vacuum leakage around the shaft 236.The actuator 234 allows the substrate support 232 to be moved verticallywithin the chamber body 212 between a processing position and a loadingposition. The loading position is slightly below the opening of a tunnel(not shown) formed in a sidewall of the chamber body 212.

The substrate support 232 has a flat, or a substantially flat, substratesupporting surface for supporting a substrate to be processed thereon.The substrate support 232 may be moved vertically within the chamberbody 212 by actuator 234, which is coupled to the substrate support 232by shaft 236. For some steps, the substrate support 232 may be elevatedto a position in close proximity to the lid assembly 214 to control thetemperature of the substrate 210 being processed. As such, the substrate210 may be heated via radiation emitted from the second gas distributor230, or another radiant source, or by convection or conduction from thesecond gas distributor 230 through an intervening gas. In some processsteps, the substrate may be disposed on lift pins 251 to performadditional thermal processing steps, such as performing an annealingstep.

FIG. 2C is an enlarged cross-sectional view of the substrate support 232of FIG. 2A. The substrate support 232 includes a thermal control plenum235 in fluid communication with a fluid supply conduit 241 and a fluidreturn conduit 243, each of the conduits 241 and 243 disposed throughthe shaft 236. The thermal control plenum 235 may be a cooling featurefor the substrate support 232 by circulating a cooling fluid through thefluid supply conduit 241, into the thermal control plenum 235, and outthrough the fluid return conduit 243.

The substrate support 232 may also include a plurality of heaters 237and 239. The plurality of heaters, in this embodiment, includes a firstheater 237 and a second heater 239. The first and second heaters 237 and239 are disposed in a substantially coplanar relationship within thesubstrate support 232 at a location to enable thermal coupling betweenthe heaters and the substrate supporting surface. The first heater 237is disposed at a periphery of the substrate support 232, and the secondheater 239 is disposed in a central area of the substrate support 232,to provide zonal temperature control. Each of the first and secondheaters 237 and 239 may be resistive heaters that are coupled to powersources (not shown) by respective power conduits 249 and 247, eachdisposed through the shaft 236.

In operation, temperature control may be provided by concurrentoperation of the thermal control plenum 235 and the heaters 237 and 239.The thermal control plenum 235 may be supplied with a cooling fluid, asdescribed above, and power may be provided to the heaters 237 and 239,as resistive heaters. In this way, separate control circuits may betuned to provide fast response for one item, for example the heaters 237and 239, and slower response for the thermal control plenum 235, or viceversa. At a minimum, different control parameters may be applied to thethermal control plenum 235, the first heater 237, and the second heater239 to accomplish an optimized, zonal temperature control system.

As shown in FIG. 2C, a separate lift member 245 may be included in thesupport assembly 216. A recess may be provided in the substratesupporting surface to accommodate the lift pins 251 of the member 245when the substrate rests on the substrate supporting surface. The liftmember 245 may be coupled to a lift actuator 255 by an extension of thelift member 245 disposed through the shaft 236. The lift actuator maymove the lift member 245 vertically to lift the substrate off thesubstrate supporting surface toward the first gas distributor 272. Thelift member 245 may be a hoop, such as an open hoop or a closed hoop,which may be U-shaped, circular, horseshoe-shaped, or any convenientshape. The lift member 245 has a thickness to provide structuralstrength when lifting a substrate. In one example, the lift member ismade of a ceramic material and is about 1 mm thick.

FIG. 3 illustrates single substrate chemical vapor deposition (CVD)reactor 300, including a quartz process chamber or reaction chamber 305,according to one embodiment. The reactor 300 may be utilized for CVD ofa number of different materials, including SiGe and Ge films asdisclosed herein. Moreover, the illustrated reactor 300 can accomplishmultiple deposition steps in the same chamber 305, as will be apparentfrom the discussion below.

The reactor 300 may generally have the shape of a rectangular box. Aplurality of radiant heat sources is supported outside the processchamber 305 to provide heat energy in the process chamber 305 withoutappreciable absorption by walls of the process chamber 305. While theembodiments are described in the context of a “cold wall” CVD reactorfor processing semiconductor substrates, it will be understood that themethods described herein will have utility in conjunction with otherheating/cooling systems, such as those employing inductive or resistiveheating.

The radiant heat sources comprise an upper heating assembly comprising aplurality of elongated heating elements 310 (only one is shown in thisview). The heating elements 310 are elongated tube-type radiant heatingelements, such as lamps. The heating elements 310 are disposed inspaced-apart parallel relationship and also substantially parallel witha reactant gas flow path (shown by arrow 312) through the processchamber 305. A lower heating assembly comprises similar heating elements315, such as lamps, positioned below the process chamber 305, andoriented transverse to the heating elements 310. A portion of theradiant heat is diffusely reflected into the process chamber 305 byrough specular reflector plates (not shown) above and below the upperand lower heating elements 310, 315, respectively. Additionally, aplurality of spot lamps 320 supply concentrated heat to the underside ofthe substrate support structure (described below), to counteract a heatsink effect created by cold support structures extending through thebottom of the process chamber 305. In some embodiments, each of theheating elements 310, 315 is a high intensity tungsten filament lampproducing radiant heat energy transmitted through the walls of theprocess chamber 305 without appreciable absorption. As is known in theart of semiconductor processing equipment, the power of the variousheating elements 310, 315, 320 can be controlled independently or ingrouped zones in response to temperature sensors.

A workpiece, comprising a silicon substrate 325, is shown supportedwithin the process chamber 305 upon a substrate support structure 330.The illustrated support structure 330 includes a substrate holder 332,upon which the substrate 325 rests, and a support spider 334. The spider334 is mounted to a shaft 336, which extends downwardly through a tube338 extending through the chamber lower wall. The tube 338 communicateswith a source of purge gas which can flow during processing of asubstrate. The purge gas may be utilized to inhibit process gases fromentering the lower section of the process chamber 305. The purge gas mayalso flow horizontally beneath the substrate 325.

A plurality of temperature sensors is positioned in proximity to thesubstrate 325. The temperature sensors may take a variety of forms, suchas optical pyrometers or thermocouples. In the illustrated embodiment,the temperature sensors comprise thermocouples, including a first orcentral thermocouple 340, suspended below the substrate holder 332 inany suitable fashion. The central thermocouple 340 passes through thespider 334 in proximity to the substrate holder 332. The reactor 300further includes a plurality of secondary or peripheral thermocouples,also in proximity to the substrate 325, including a leading edge orfront thermocouple 345, a trailing edge or rear thermocouple 350, and aside thermocouple (not shown). Each of the peripheral thermocouples ishoused within a slip ring 352, which surrounds the substrate holder 332and the substrate 325. Each of the central and peripheral thermocouplesare connected to a temperature controller, which sets the power of thevarious heating elements 310, 315, 320 in response to the readings ofthe thermocouples.

In addition to housing the peripheral thermocouples, the slip ring 352absorbs and emits radiant heat during high temperature processing. Theslip ring 352 may be utilized to compensate for a greater heat loss orabsorption at the substrate edges, a phenomenon which is known to occurdue to a greater ratio of surface area to volume in regions near thesubstrate edges. By minimizing edge losses, slip ring 352 can reduce therisk of radial temperature non-uniformities across the substrate 325.The slip ring 352 can be suspended by any suitable means. For example,the illustrated slip ring 352 rests upon support members 354, whichextend from a front chamber divider 356, and a rear chamber divider 358.The dividers 356, 358 desirably are formed of quartz. In somearrangements, the rear divider 358 can be omitted.

The illustrated process chamber 305 includes an inlet port 360 for theinjection of reactant and carrier gases, and the substrate 325 can alsobe received therethrough. An outlet port 364 is on the opposite side ofthe process chamber 305, with the substrate support structure 330positioned between the inlet port 360 and outlet port 364.

An inlet component 365 is fitted to the process chamber 305, adapted tosurround the inlet port 360, and includes a horizontally elongated slot367 through which the substrate 325 can be inserted. A generallyvertical inlet 368 receives gases from gas sources and communicates suchgases with the slot 367 and the inlet port 360. While not separatelyillustrated in FIG. 3, the gas sources may include hydrogen, silicon andgermanium precursors, and a controller (e.g., preprogrammed computer)that controls a sequence of steps as described herein, including flowingthe surface active compound into the chamber during a cool down stepprior to Si and/or Ge deposition. The inlet 368 can include gasinjectors designed to maximize uniformity of gas flow for thesingle-substrate reactor.

An outlet component 370 similarly mounts to the process chamber 305 suchthat an exhaust opening 372 aligns with the outlet port 364 and leads toexhaust conduits 374. The conduits 374, in turn, can communicate withsuitable vacuum means (not shown) for exhausting process gases from theprocess chamber 305. In one embodiment, process gases are drawn throughthe process chamber 305 and a downstream scrubber (not shown). A pump orfan is preferably included to aid in drawing process gases through theprocess chamber 305, and to evacuate the chamber for reduced pressureprocessing, i.e., below atmospheric pressure but above ultra-high vacuumpressure ranges, as discussed below.

The illustrated reactor 300 also includes a source 376 of excitedspecies, positioned upstream from the reactor 300. The excited speciessource 376 of the illustrated embodiment comprises a remote plasmagenerator, including a magnetron power generator and an applicator alonga gas line 378. In the illustrated embodiment, microwave energy from amagnetron is coupled to a flowing gas in an applicator along the gasline 378. A precursor gas source 380 is coupled to the gas line 378 forintroduction into the excited species source 376. A carrier gas source382 is also coupled to the gas line 378. One or more branch lines 384can also be provided for additional reactants. As is known in the art,the gas sources 380, 382 can comprise gas tanks, bubblers, etc.,depending upon the form and volatility of the reactant species. Each gasline can be provided with a separate mass flow controller (MFC) andvalves, as shown, to allow selection of relative amounts of carrier andreactant species introduced to the source 376 and thence into theprocess chamber 305. The excited species source 376 can be employed forplasma enhanced deposition, but also may be utilized for excitingetchants for cleaning the chamber 305 of excess deposition when nosubstrate is in the chamber 305.

The total volume capacity of the single-substrate process chamber 305designed for processing 200 mm substrates, for example, is less thanabout 30 liters, such as less than about 20 liters, and in oneembodiment is less than about 10 liters. The illustrated chamber 305 hasa capacity of about 7.5 liters. Because the illustrated process chamber305 is partitioned by the dividers 356, 358, substrate holder 332, ring352, and the purge gas flowing from the tube 338, the effective volumethrough which process gases flow is around half the total volume (e.g.,about 3.77 liters in the illustrated embodiment). It is understood thatthe volume of the single-substrate process chamber 305 can be different,depending upon the size of the substrates for which the process chamber305 is designed to accommodate. For example, a single-substrate processchamber 305 for 300 mm substrates has a capacity of less than about 100liters, such as about 60 liters, and in one embodiment is less thanabout 30 liters. In one example, the single-substrate process chamber305 for processing a 300 mm substrate has a total volume of about 24liters, with an effective volume of about 12 liters.

Deposition temperatures for a Ge-containing layer are typically in therange of about 250 degrees Celsius (C) to about 600 degrees C., forexample about 300 degrees C. to about 450 degrees C. For example, lowerdeposition temperatures tend to be more appropriate as the thermalstability of the precursor decreases. The total pressure in thesingle-substrate process chamber 305 is in the range of about 10-5 Torrto about 800 Torr. In some embodiments, the pressure is about 200 mTorrto about 760 Torr, such as about 1 Torr to about 200 Torr, for exampleabout 1 Torr to about 60 Torr.

FIG. 4 illustrates a schematic sectional view of a backside heatingprocess chamber 400 configured for low pressure epitaxial depositionaccording to one embodiment. The process chamber 400 may be used toprocess one or more substrates, including the deposition of a materialon an upper surface of a substrate 325. The process chamber 400 mayinclude an array of radiant heating lamps 402 for heating, among othercomponents, a back side 404 of a substrate support 406 disposed withinthe process chamber 400. The substrate support 406 may be a disk-likesubstrate support 406 as shown, or may be a ring-like substrate support(having a central opening), which supports the substrate from the edgeof the substrate to facilitate exposure of the substrate to the thermalradiation of the lamps 402.

The substrate support 406 is located within the process chamber 400between an upper dome 428 and a lower dome 414. The upper dome 428, thelower dome 414 and a base ring 436 that is disposed between the upperdome 428 and lower dome 414 generally define an internal region of theprocess chamber 400. The substrate 325 (not to scale) is transferredinto the process chamber 400 and positioned onto the substrate support406 through a loading port not shown in this view.

The substrate support 406 is supported by a central shaft 432, whichmoves the substrate 325 in a vertical direction 434 during loading andunloading, and in some instances, processing of the substrate 325. Thesubstrate support 406 is shown in an elevated processing position inFIG. 4, but may be vertically traversed by an actuator (not shown)coupled to the central shaft 432 to a loading position below theprocessing position. When lowered below the processing position, liftpins (not shown) contact the substrate 325 and raise the substrate 325from the substrate support 406. A robot (not shown) may then enter theprocess chamber 400 to engage and remove the substrate 325 therefromthough the loading port. The substrate support 406 then may be actuatedvertically to the processing position to place the substrate 325, withits device side 416 facing up, on a front side 410 of the substratesupport 406.

The substrate support 406, while located in the processing position,divides the internal volume of the process chamber 400 into a processgas region 456 that is above the substrate 325, and a purge gas region458 below the substrate support 406. The substrate support 406 isrotated during processing by the central shaft 432 to minimize theeffect of thermal and process gas flow spatial anomalies within theprocess chamber 400 and thus facilitate uniform processing of thesubstrate 325. The substrate support 406 may be formed from siliconcarbide or graphite coated with silicon carbide to absorb radiant energyfrom the lamps 402 and conduct the radiant energy to the substrate 325.

In general, the central window portion of the upper dome 428 and thebottom of the lower dome 414 are formed from an optically transparentmaterial such as quartz. The thickness and the degree of curvature ofthe upper dome 428 may be configured to provide a flatter geometry foruniform flow uniformity in the process chamber.

The array of lamps 402 can be disposed adjacent to and beneath the lowerdome 414 in a specified, optimal desired manner around the central shaft432 to independently control the temperature at various regions of thesubstrate 325 as the process gas passes over, which facilitates thedeposition of a material onto the upper surface of the substrate 325.While not discussed here in detail, the deposited material may includegallium arsenide, gallium nitride, or aluminum gallium nitride. In someembodiments, an array of radiant heating lamps, such as the lamps 402,may be disposed over the upper dome 428.

The lamps 402 may be configured to include bulbs configured to heat thesubstrate 325 to a temperature within a range of about 200 degrees C. toabout 1600 degrees C. Each lamp 402 is coupled to a power distributionboard (not shown) through which power is supplied to each lamp 402. Thelamps 402 are positioned within a lamphead 445 which may be cooledduring or after processing by, for example, a cooling fluid introducedinto channels 449 located between the lamps 402. The lamphead 445conductively and radiatively cools the lower dome 414 due in part to theclose proximity of the lamphead 445 to the lower dome 414. The lamphead445 may also cool the lamp walls and walls of reflectors (not shown)around the lamps. Alternatively, the lower dome 414 may be cooled by aconvective approach. Depending upon the application, the lamphead 445may or may not be in contact with the lower dome 414.

A circular shield 467 may be optionally disposed around the substratesupport 406 and surrounded by a liner assembly 463. The shield 467prevents or minimizes leakage of heat/light noise from the lamps 402 tothe device side 416 of the substrate 325 while providing a pre-heat zonefor the process gases. The shield 467 may be made from CVD SiC, sinteredgraphite coated with SiC, grown SiC, opaque quartz, coated quartz, orany similar, suitable material that is resistant to chemical breakdownby process and purging gases.

The liner assembly 463 is sized to be nested within or surrounded by aninner circumference of the base ring 436. The liner assembly 463 shieldsthe processing volume (i.e., the process gas region 456 and purge gasregion 458) from metallic walls of the process chamber 400. The metallicwalls may react with precursors and cause contamination in theprocessing volume. While the liner assembly 463 is shown as a singlebody, the liner assembly 463 may include one or more liners withdifferent configurations.

As a result of backside heating of the substrate 325 from the substratesupport 406, the use of an optical pyrometer 418 for temperaturemeasurements/control on the substrate support can be performed. Thistemperature measurement by the optical pyrometer 418 may also be done onthe device side 416 of the substrate 325, having an unknown emissivity,since heating the substrate front side 410 in this manner is emissivityindependent. As a result, the optical pyrometer 418 can only senseradiation from the hot substrate 325 that conducts heat from thesubstrate support 406, with minimal background radiation from the lamps402 directly reaching the optical pyrometer 418.

A reflector 422 may be optionally placed outside the upper dome 428 toreflect light that is radiating off the substrate 325 back onto thesubstrate 325. The reflector 422 may be secured to the upper dome 428using a clamp ring 430. The reflector 422 can be made of a metal such asaluminum or stainless steel. The efficiency of the reflection can beimproved by coating a reflector area with a highly reflective coatingsuch as gold. The reflector 422 can have one or more channels 426connected to a cooling source (not shown). The channels 426 connect to apassage (not shown) formed on a side of the reflector 422 for coolingthe reflector 422. The passage is configured to carry a flow of a fluidsuch as water and may run horizontally along the side of the reflector422 in any desired pattern covering a portion or entire surface of thereflector 422.

Process gas supplied from a process gas supply source 472 is introducedinto the process gas region 456 through a process gas inlet 474 formedin the sidewall of the base ring 436. The process gas inlet 474 isconfigured to direct the process gas in a generally radially inwarddirection. During the film formation process, the substrate support 406may be located in the processing position, which is adjacent to and atabout the same elevation as the process gas inlet 474, allowing theprocess gas to flow up and round along flow path 473 across the uppersurface of the substrate 325 in a laminar flow. The process gas exitsthe process gas region 456 (along flow path 475) through a gas outlet478 located on the side of the process chamber 400 opposite the processgas inlet 474. Removal of the process gas through the gas outlet 478 maybe facilitated by a vacuum pump 480 coupled thereto. As the process gasinlet 474 and the gas outlet 478 are aligned with each other anddisposed approximately at the same elevation, it is believed that such aparallel arrangement, when combined with a flatter upper dome 428enables a generally planar, uniform gas flow across the substrate 325.Further radial uniformity may be provided by the rotation of thesubstrate 325 through the substrate support 406.

A purge gas may be supplied from a purge gas source 462 to the purge gasregion 458 through an optional purge gas inlet 464 (or through theprocess gas inlet 474) formed in the sidewall of the base ring 436. Thepurge gas inlet 464 is disposed at an elevation below the process gasinlet 474. If the circular shield 467 or a pre-heat ring (not shown) isused, the circular shield or the pre-heat ring may be disposed betweenthe process gas inlet 474 and the purge gas inlet 464. In either case,the purge gas inlet 464 is configured to direct the purge gas in agenerally radially inward direction. During the film formation process,the substrate support 406 may be located at a position such that thepurge gas flows down and round along flow path 465 across the back side404 of the substrate support 406 in a laminar flow. Without being boundby any particular theory, the flowing of the purge gas is believed toprevent or substantially avoid the flow of the process gas from enteringinto the purge gas region 458, or to reduce diffusion of the process gasentering the purge gas region 458 (i.e., the region under the substratesupport 406). The purge gas exits the purge gas region 458 (along flowpath 466) and is exhausted out of the process chamber through the gasoutlet 478, which is located on the side of the process chamber 400opposite the purge gas inlet 464.

FIG. 5 is a schematic cross-sectional view of a CVD or epitaxialdeposition process chamber 500, which may be part of a CENTURA®integrated processing system available from Applied Materials, Inc., ofSanta Clara, Calif. The process chamber 500 includes housing structure501 made of a process resistant material, such as aluminum or stainlesssteel, for example 316 L stainless steel. The housing structure 501encloses various functioning elements of the process chamber 500, suchas a quartz chamber 530, which includes an upper chamber 505, and alower chamber 524, in which a processing volume 518 is contained.Reactive species are provided to the quartz chamber 530 by a gasdistribution assembly 550, and processing byproducts are removed fromprocessing volume 518 by an outlet port 538, which is typically incommunication with a vacuum source (not shown).

A substrate support 517 is adapted to receive a substrate 325 that istransferred to the processing volume 518. The substrate support 517 isdisposed along a longitudinal axis 502 of the process chamber 500. Thesubstrate support 517 may be made of a ceramic material or a graphitematerial coated with a silicon material, such as silicon carbide, orother process resistant material. Reactive species from precursorreactant materials are applied to a surface 516 of the substrate 325,and byproducts may be subsequently removed from the surface 516. Heatingof the substrate 325 and/or the processing volume 518 may be provided byradiation sources, such as upper lamp modules 510A and lower lampmodules 5106.

In one embodiment, the upper lamp modules 510A and lower lamp modules5106 are infrared (IR) lamps. Non-thermal energy or radiation from lampmodules 510A and 5106 travels through upper quartz window 504 of upperquartz chamber 505, and through the lower quartz window 503 of lowerquartz chamber 524. Cooling gases for upper quartz chamber 505, ifneeded, enter through an inlet 512 and exit through an outlet 513.Precursor reactant materials, as well as diluent, purge and vent gasesfor the process chamber 500, enter through gas distribution assembly 550and exit through outlet port 538. While the upper quartz window 504 isshown as being curved or convex, the upper quartz window 504 may beplanar or concave as the pressure on both sides of the upper quartzwindow 504 is substantially the same (i.e., atmospheric pressure).

The low wavelength radiation in the processing volume 518, which is usedto energize reactive species and assist in adsorption of reactants anddesorption of process byproducts from the surface 516 of substrate 325,typically ranges from about 0.8 μm to about 1.2 μm, for example, betweenabout 0.95 μm to about 1.05 μm, with combinations of various wavelengthsbeing provided, depending, for example, on the composition of the filmwhich is being epitaxially grown.

The component gases enter the processing volume 518 via gas distributionassembly 550. Gas flows from the gas distribution assembly 550 and exitsthrough port 538 as shown generally at 522. Combinations of componentgases, which are used to clean/passivate a substrate surface, or to formthe silicon and/or germanium-containing film that is being epitaxiallygrown, are typically mixed prior to entry into the processing volume.The overall pressure in the processing volume 518 may be adjusted by avalve (not shown) on the outlet port 538. At least a portion of theinterior surface of the processing volume 518 is covered by a liner 531.In one embodiment, the liner 531 comprises a quartz material that isopaque. In this manner, the chamber wall is insulated from the heat inthe processing volume 518.

The temperature of surfaces in the processing volume 518 may becontrolled within a temperature range of about 200° C. to about 600° C.,or greater, by the flow of a cooling gas, which enters through inlet 512and exits through outlet 513, in combination with radiation from upperlamp modules 510A positioned above upper quartz window 504. Thetemperature in the lower quartz chamber 524 may be controlled within atemperature range of about 200° C. to about 600° C. or greater, byadjusting the speed of a blower unit which is not shown, and byradiation from the lower lamp modules 5106 disposed below lower quartzchamber 524. The pressure in the processing volume 518 may be betweenabout 0.1 Torr to about 600 Torr, such as between about 5 Torr to about30 Torr.

The temperature on the substrate 325 surface 516 may be controlled bypower adjustment to the lower lamp modules 5106 in lower quartz chamber524, or by power adjustment to both the upper lamp modules 510Aoverlying upper quartz window 504, and the lower lamp modules 5106 inlower quartz chamber 524. The power density in the processing volume 518may be between about 40 W/cm² to about 400 W/cm², such as about 80 W/cm²to about 120 W/cm².

In one aspect, the gas distribution assembly 550 is disposed normal to,or in a radial direction 506 relative to, the longitudinal axis 502 ofthe process chamber 500 or substrate 325. In this orientation, the gasdistribution assembly 550 is adapted to flow process gases in a radialdirection 506 across, or parallel to, the surface 516 of the substrate325. In one processing application, the process gases are preheated atthe point of introduction to the process chamber 500 to initiatepreheating of the gases prior to introduction to the processing volume518, and/or to break specific bonds in the gases. In this manner,surface reaction kinetics may be modified independently from the thermaltemperature of the substrate 325.

In operation, precursors to form Si and SiGe blanket or selective filmsare provided to the gas distribution assembly 550 from the one or moregas sources 540A and 540B. IR lamps 556 (only one is shown in FIG. 5)may be utilized to heat the precursors within the gas distributionassembly 550 as well as along the flow path 522. The gas sources 540A,540B may be coupled the gas distribution assembly 550 in a mannerconfigured to facilitate introduction zones within the gas distributionassembly 550, such as a radial outer zone and a radial inner zonebetween the outer zones when viewed in from a top plan view. The gassources 540A, 540B may include valves (not shown) to control the rate ofintroduction into the zones.

The gas sources 540A, 540B may include silicon precursors such assilanes, including silane (SiH₄), disilane (Si₂H₆), dichlorosilane(SiH₂Cl₂), hexachlorodisilane (Si₂Cl₆), dibromosilane (SiH₂Br₂), higherorder silanes, derivatives thereof, and combinations thereof. The gassources 540A, 540B may also include germanium containing precursors,such as germane (GeH₄), digermane (Ge₂H₆), germanium tetrachloride(GeCl₄), dichlorogermane (GeH₂Cl₂), derivatives thereof, andcombinations thereof. The silicon and/or germanium containing precursorsmay be used in combination with hydrogen chloride (HCl), chlorine gas(Cl₂), hydrogen bromide (HBr), and combinations thereof. The gas sources540A, 540B may include one or more of the silicon and germaniumcontaining precursors in one or both of the gas sources 540A, 540B.

The precursor materials enter the processing volume 518 through openingsor a plurality of holes 558 (only one is shown in FIG. 5) in theperforated plate 554 in this excited state, which in one embodiment is aquartz material, having the holes 558 formed therethrough. Theperforated plate 554 is transparent to IR energy, and may be made of aclear quartz material. In other embodiments, the perforated plate 554may be any material that is transparent to IR energy and is resistant toprocess chemistry and other processing chemistries. The energizedprecursor materials flow toward the processing volume 518 through theplurality of holes 558 in the perforated plate 554, and through aplurality of channels 552N (only one is shown in FIG. 5). A portion ofthe photons and non-thermal energy from the IR lamps 556 also passesthrough the holes 558, the perforated plate 554, and channels 552Nfacilitated by a reflective material and/or surface disposed on theinterior surfaces of the gas distribution assembly 550, therebyilluminating the flow path of the precursor materials (shown as arrow522 in FIG. 5). In this manner, the vibrational energy of the precursormaterials may be maintained from the point of introduction to theprocessing volume 518 along the flow path.

FIG. 6 illustrates an exemplary vacuum processing system 600 that can beused to complete the processing sequence 100 illustrated in FIG. 1,according to implementations of the present disclosure. As shown in FIG.6, a plurality of processing chambers 602 a, 602 b, 602 c, 602 d arecoupled to a first transfer chamber 604. The processing chambers 602a-602 d may be used to perform any substrate related processes, such asannealing, chemical vapor deposition, physical vapor deposition,epitaxial process, etching process, thermal oxidation or thermalnitridation process, degassing etc. In one implementation, theprocessing chamber 602 a may be a film formation chamber, such as avapor phase epitaxy deposition chamber, for example an Epi chamberavailable from Applied Materials, Santa Clara, Calif., that is capableof forming a crystalline silicon or silicon germanium. In anotherimplementation, the processing chamber 602 a may be an epitaxydeposition chamber such as the single-substrate processing chamber(e.g., the reactor 300 described in connection with FIG. 3). In anotherimplementation, the processing chamber 602 a may be the process chamber400 described in connection with FIG. 4. In another implementation, theprocessing chamber 602 a may be the process chamber 500 described inconnection with FIG. 5.

The processing chamber 602 b may be a rapid thermal processing chamber(RTP). The processing chamber 602 c is a plasma etching chamber or aplasma cleaning chamber. For example the processing chamber 602 c may bethe processing chamber 200 described in connection with FIG. 2A or theprocessing chamber 300 described in connection with FIG. 3. Theprocessing chamber 602 d may be a degassing chamber. The first transferchamber 604 is also coupled to at least one transition station, forexample a pair of pass-through stations 606, 608. The pass-throughstations 606, 608 maintain vacuum conditions while allowing substratesto be transferred between the first transfer chamber 604 and a secondtransfer chamber 610. The first transfer chamber 604 has a roboticsubstrate handling mechanism (not shown) for transferring substratesbetween the pass-through stations 606, 608 and any of the processingchambers 602 a-602 d. The processing chambers 602 a-602 d are shownconfigured in a certain order in FIG. 6, but they may be configured inany desired order.

One end of the pass-through stations 606, 608 is coupled to the secondtransfer chamber 610. Therefore, the first transfer chamber 604 and thesecond transfer chamber 610 are separated and connected by thepass-through stations 606, 608. The second transfer chamber 610 iscoupled to a first plasma-cleaning chamber 614, which can be a plasmachamber such as the processing chamber 200 (FIG. 2A) that is adapted toperform at least some of the processes found in box 602 for removingoxides from a surface of a substrate. In one implementation, the firstplasma-cleaning chamber 614 is a Siconi™ or Selectra™ chamber, which isavailable from Applied Materials, Santa Clara, Calif. In anotherimplementation, the plasma cleaning chamber 614 may be the processingchamber 200 described in connection with FIG. 2A. In anotherimplementation, the plasma cleaning chamber 614 may be the processingchamber 300 described in connection with FIG. 3.

In one implementation, the at least one transition station, for exampleone of the pass-through stations 606, 608, is configured to be aplasma-cleaning chamber. Alternatively, a plasma-cleaning chamber may becoupled to one of the pass-through stations 606, 608 for removingcontaminants from the surface of the substrate. Thus, the processingsystem 600 may have a second plasma-cleaning chamber that is, or isconnected to, one of the pass-through stations 606, 608. In oneimplementation shown in FIG. 6, the pass-through station 606 includes asecond plasma-cleaning chamber 616. The second plasma-cleaning chamber616 may be a version of the processing chamber 300 (FIG. 3) that isadapted to perform at least some of the processes found in box 102 forremoving contaminants from the surface of the substrate. It should benoted that, although only one plasma-cleaning chamber 616 is showncoupled to a pass-through station, in this case the pass-through station606, a plasma-cleaning chamber (e.g., a version of the processingchamber 300) may be coupled to both the pass-through stations 606 and608.

The second transfer chamber 610 also has a robotic substrate handlingmechanism (not shown) for transferring substrates between a set of loadlock chamber 612 and the first plasma-cleaning chamber 614 or the secondplasma-cleaning chamber 616. A factory interface 620 is connected to thesecond transfer chamber 610 by the load lock chambers 612. The factoryinterface 620 is coupled to one or more pods 630 on the opposite side ofthe load lock chambers 612. The pods 630 typically are front openingunified pods (FOUP) that are accessible from a clean room (not shown).

While two transfer chambers are shown, it is contemplated that any ofthe transfer chambers may be omitted. In one implementation where thesecond transfer chamber 610 is omitted, the second plasma-cleaningchamber 616 may be disposed within or coupled to the first transferchamber 604 at the location currently shown as occupied by thepass-through stations 606 or 608. The first transfer chamber 604 may becoupled to one or more processing chambers capable of formingcrystalline silicon or silicon germanium, such as an epitaxy chamber,for example a Centura™ Epi chamber available from Applied Materials,Inc., of Santa Clara, Calif. Alternatively, the first transfer chamber604 may be omitted and the second plasma-cleaning chamber 616 may bedisposed within or coupled to the pass-through station 606, which iscoupled to the second transfer chamber 610. In such a case, the secondtransfer chamber 610 may be configured to be coupled to one or moreprocessing chambers capable of forming crystalline silicon or silicongermanium.

In operation, substrates are carried from pods 630 to the vacuumprocessing system 600 in a transport cassette (not shown) that is placedwithin one of the load lock chambers 612. The robotic transportmechanism within the second transfer chamber 610 transports thesubstrates, one at a time, from the load lock chambers 612 to the firstplasma-cleaning chamber 614 where the a cleaning process, e.g.,processes found in box 102, is performed to remove oxides from a surfaceof a substrate. Once the oxides have been removed from the substratesurface, the robotic transport mechanism disposed within the secondtransfer chamber 610 transfers the substrate from the firstplasma-cleaning chamber 614 to the second plasma-cleaning chamber 616where a reducing process, e.g., processes found in box 103, is performedto remove contaminants such as carbon or hydrocarbons from the substratesurface. It is contemplated that the steps here may also be performed inthe reverse order, i.e., using the robotic transport mechanism totransfer the substrate from the second plasma-cleaning chamber 616 tothe first plasma-cleaning chamber 614. In either case, the cleansubstrates are then transferred by the robotic transport mechanismdisposed within the first transfer chamber 604 from the secondplasma-cleaning chamber 616 (or the first plasma-cleaning chamber 614)to one or more processing chambers 602 a-602 d. The one or moreprocessing chambers 602 a-602 d may include an epitaxy process chamberwhere a layer formation process, such as the epitaxial depositiondescribed in box 106, is performed.

Upon completion of processing in the one or more processing chambers 602a-602 d, the robotic transport mechanism disposed within the firsttransfer chamber 604 moves the substrate from either one of theprocessing chambers 602 to the pass-through station 608. The substrateis then removed from the pass-through station 608 by the robotictransport mechanism disposed within the second transfer chamber 610 andtransferred to the other load lock chamber 612 through which it iswithdrawn from the vacuum processing system 600.

Since the processes of all three boxes 102, 103 and 106 of FIG. 1 areperformed within the same vacuum processing system 600, vacuum is notbroken as the substrate is transferred among various chambers, whichdecreases the chance of contamination and improves the quality of thedeposited epitaxial film. It should be understood that the movement ofthe substrates is described herein for illustration purposes. Acontroller (not shown) may be used to schedule the movement of thesubstrates through the vacuum processing system 600 in accordance with adesired sequencing program, which may vary depending upon theapplication.

Benefits of the present disclosure include an improved vacuum processingsystem integrating two different types of pre-clean process chamberswith the epitaxial process chamber on the same vacuum processing system.The pre-clean process chambers may include a first plasma-cleaningprocess chamber and a second plasma-cleaning process chamber.Co-existence of two types of surface materials removal chamber on thesame vacuum processing system allows substrates to remain in vacuumbetween surface preparation and epitaxial deposition, which reduces thetime the substrates are exposed to ambient and eliminates the need toprepare the substrates on a separate processing chamber or system. Thisarchitecture also maximizes the number of process chambers on a vacuumsystem because the pass-through station between two transfer chambersalso functions as a pre-clean process chamber, which also reducesoverall handling time of the substrates.

An example of the process 102 of FIG. 1 can be performed in theprocessing chamber 200 of FIG. 2A. Argon is routed through the remoteplasma unit 224, a first mixture of 5-10% HF in argon is routed throughthe inlet 256, and a second mixture of 25% NH₃ in argon is routedthrough the inlet 258. The remote plasma is formed by applying 500 W ofmicrowave or RF power to argon gas flowing at 2 sLm. The first mixtureis flowed through the first inlet 256 at 500 sccm and the second mixtureis flowed through the second inlet 258 at 500 sccm. The substrate ismaintained at a temperature of 10 degrees Celsius by routing temperaturecontrol fluid through the thermal control plenum 235. The substratesupport 232 may be powered to provide radial temperature control. Thechamber is maintained at a pressure of 5 Torr, and the substrate isprocessed for a time suitable for converting all desired oxides on thesubstrate surface into sublimable solid, for example 300 seconds. Thesubstrate is then moved close to the second gas distributor 230, whichis heated to about 200 degrees Celsius to provide radiant or conductiveheating to the substrate surface. The substrate is maintained inproximity to the heat radiating from the second gas distributor 230 for1-5 minutes to sublime the solids formed on the substrate surface,leaving an oxygen-free surface. The substrate may then be optionallyheat-treated under an inert atmosphere to remove any residual speciesfrom the oxide removal process, such as fluorine containing species. Theheat treatment may include disposing the substrate in a thermaltreatment chamber and energizing a thermal treatment apparatus in thechamber to heat the substrate to a temperature of about 300 degreesCelsius for about 1 minute.

While the foregoing is directed to implementations of the presentdisclosure, other and further implementations of the disclosure may bedevised without departing from the basic scope thereof.

1. A method of processing a substrate, comprising: removing oxide from asubstrate by a process that includes exposing the substrate to aprocessing gas comprising NH₃, HF, and radicals; and forming a film onthe substrate by a vapor phase epitaxy process.
 2. The method of claim9, further comprising cooling the substrate while removing oxide fromthe substrate.
 3. The method of claim 9, further comprising performing athermal treatment process the substrate after removing oxide from thesubstrate.
 4. The method of claim 11, wherein the thermal treatmentprocess is performed under an inert atmosphere at a temperature of 400degrees Celsius or higher.
 5. The method of claim 9, wherein the oxideremoval process comprises: disposing the substrate in a processingchamber; forming a plasma from an inert gas; flowing the plasma into amixing chamber with NH₃ and HF to form a reaction mixture; flowing thereaction mixture into the processing chamber, and exposing the substrateto the reaction mixture.
 6. The method of claim 13, wherein the oxideremoval process further comprises heating the substrate to a temperatureof at least 100 degrees Celsius after the exposure to the reactionmixture.
 7. The method of claim 14, further comprising: after removingoxide from the substrate, performing a thermal treatment process on thesubstrate, comprising disposing the substrate in a thermal treatmentchamber; flowing an inert gas into the thermal treatment chamber; andheating the substrate to a temperature of 400 degrees Celsius orgreater.
 8. The method of claim 15, wherein the forming the film on thesubstrate is performed in the same chamber as the thermal treatment. 9.The method of claim 16, wherein performing the thermal treatment processfurther comprises exposing the substrate to a hydrogen containing gas.